macOS: support Japanese input for text buttons

Blender did not support to input East Asian characters (Chinese, Japanese,
Korean) on macOS. This patch adds support for Japanese input, by implementing
the appropriate processing for the NSTextInputClient protocol.

Technical notes:
* The conversion candidate window is drawn by the input method program calling
  `firstRectForCharacterRange`.
* The string before confirmation (called `composite` in blender) is handled in
  the `setMarkedText` method called by the input method program.
* The string after confirmation (called `result` in the blender) is processed
  in the `insertText` method called by the input method program.

Ref T51283

Differential Revision: https://developer.blender.org/D11695

1 files changed, 23 insertions, 0 deletions

diff --git a/intern/ghost/intern/GHOST_WindowCocoa.mm b/intern/ghost/intern/GHOST_WindowCocoa.mm
index d082fa99ad8..cea2969739c 100644
--- a/intern/ghost/intern/GHOST_WindowCocoa.mm
+++ b/intern/ghost/intern/GHOST_WindowCocoa.mm
@@ -1221,3 +1221,26 @@ GHOST_TSuccess GHOST_WindowCocoa::setWindowCustomCursorShape(GHOST_TUns8 *bitmap
   [pool drain];
   return GHOST_kSuccess;
 }
+
+#ifdef WITH_INPUT_IME
+void GHOST_WindowCocoa::beginIME(
+    GHOST_TInt32 x, GHOST_TInt32 y, GHOST_TInt32 w, GHOST_TInt32 h, int completed)
+{
+  if (m_openGLView) {
+    [m_openGLView beginIME:x y:y w:w h:h completed:(bool)completed];
+  }
+  else {
+    [m_metalView beginIME:x y:y w:w h:h completed:(bool)completed];
+  }
+}
+
+void GHOST_WindowCocoa::endIME()
+{
+  if (m_openGLView) {
+    [m_openGLView endIME];
+  }
+  else {
+    [m_metalView endIME];
+  }
+}
+#endif /* WITH_INPUT_IME */